[Spatial Distribution of Soil Heavy Metals and Regional Control Strategies in China at Province Level].

It is important to understand the spatial distribution characteristics and health risks of soil heavy metals for the implementation of soil pollution control measures in different levels and regions. Based on the data of 706 core studies in the last 20 years, the spatial distribution characteristics, accumulation degree, and health risks of soil heavy metals in China were analyzed at the provincial level. The results showed that the soil heavy metals had obvious spatial differences on the provincial scale, with an overall trend of "high in the south and low in the north and high in the east and low in the west.

Magnetic biochars have lower adsorption but higher separation effectiveness for Cd from aqueous solution compared to nonmagnetic biochars.

Magnetic biochars were prepared by chemical co-precipitation of Fe/Fe onto rice straw (M-RSB) and sewage sludge (M-SSB), followed by pyrolysis treatment, which was also used to prepare the corresponding nonmagnetic biochars (RSB and SSB). The comparison of adsorption characteristics between magnetic and nonmagnetic biochars was investigated as a function of pH, contact time, and initial Cd concentration. The adsorption of nonmagnetic biochars was better described by pseudo-second-order kinetic model, and the adsorption of RSB and SSB was better described by Langmuir and Freundlich models, respectively.

High-efficiency removal capacities and quantitative adsorption mechanisms of Cd by thermally modified biochars derived from different feedstocks.

Adsorption characteristics of Cd on the three biochars modified by pyrolysis and calcination were investigated that were derived from rice straw (TRSB), chicken manure (TCMB) and sewage sludge (TSSB). The pH effect, adsorption kinetics, isotherms and thermodynamics, and desorption were determined, and qualitative analysis of adsorption mechanisms was performed by SEM, XRD, FTIR and XPS. Maximum adsorption capacities reached 177.

[Improved Regression Kriging Prediction of the Spatial Distribution of the Soil Cadmium by Integrating Natural and Human Factors].

Mastering the spatial distribution of heavy metals in the soil plays an important supporting role in the scientific formulation of soil pollution risk management and control strategies. Few factors were considered and multiple collinearity between parallel variables existed,resulting in low prediction accuracy. OK (common Kriging method), NRK (regressive Kriging method based on natural factors only), and NARK (regressive Kriging based on natural-human factors)were used to simulate the spatial distribution of soil Cd by selecting 23 natural-artificial influencing factors.

Qualitative and quantitative characterization of adsorption mechanisms for Cd by silicon-rich biochar.

The adsorption characteristics of rice-husk biochar (RHB) rich in silicon (Si) for Cd in solution and soil were investigated. Three biochars were produced at different pyrolytic temperatures of 300 °C(RHB300), 500 °C(RHB500) and 700 °C (RHB700). The pH effect, adsorption kinetics and isotherms were examined, and chemical analyses of Cd-loaded biochars were conducted by SEM-EDS, FTIR, XRD and Boehm titration.

Adsorption Behavior and Relative Distribution of Cd Adsorption Mechanisms by the Magnetic and Nonmagnetic Biochars Derived from Chicken Manure.

The present study investigated the adsorption of Cd by nonmagnetic and magnetic biochars (CMB and M-CMB) derived from chicken manure, respectively. The adsorption characteristics were investigated as a function of initial pH, contact time, initial Cd concentration and magnetic separation. Adsorption process of both biochars were better described by Pseudo-second-order kinetic equation and Freundlich isotherm model, which were spontaneous and endothermic in nature.

[Spatial Distribution and Risk Assessment of Heavy Metals in Soils from a Typical Urbanized Area].

With the rapid urbanization in China, soil environments are facing high risks. Taking a typical urbanized area as a case study, a total of 106 surface soil samples (0-20 cm) and 96 subsurface soil samples (20-40 cm) were collected to determine the concentrations of heavy metals, and then, the Nemerow index and Hankson index methods were used to evaluate their degrees of ecological risk. The spatial distributions of ecological risks were also explored.

[Pollution Characteristics and Migration of BTEX at a Chemical Contaminated Site in the Guangdong-Hong Kong-Macau Greater Bay Area].

In this study, we analyzed 247 soil and 20 groundwater samples from a typical chemical site in the Guangdong-Hong Kong-Macau Greater Bay Area and simulated the solute transport of pollutant benzene with the GMS software, in order to reconstruct the distribution and migration mechanism of benzene series (BTX) pollutants. The detected concentrations of benzene, ethylbenzene, -xylene, and -xylene exceeded the screening values in some soil and groundwater samples, indicating that the pollution of BTX in shallow groundwater was serious. Our simulation indicated an elliptical flow of benzene in groundwater (from northwest to southeast), mainly through convection, dispersion, and molecular diffusion.

[Thoughts on and Construction of a Risk Management and Control System for Contaminated Sites in the Guangdong-Hong Kong-Macao Greater Bay Area].

Preventing the environmental risks linked to contaminated sites and guaranteeing the safety of human settlements are some of the challenges and tasks involved in the construction of world-class city clusters in the Guangdong-Hong Kong-Macao Greater Bay Area. Due to differences in the political systems and land property rights between Guangdong, Hong Kong, and Macao, as well as in the levels of urbanization, industrial structures, and environmental management capabilities of the nine cities in the Pearl River Delta, the risk management and control mode of contaminated sites varies considerably within the Greater Bay Area. In this context, an analysis of the features of risk management and control in the contaminated sites of typical cities can help strengthening technical communication and cooperation, optimizing risk management and control systems.

[Classification of Priority Area for Soil Environmental Protection Around Water Sources: Method Proposed and Case Demonstration].

Based on comprehensive consideration of soil environmental quality, pollution status of river, environmental vulnerability and the stress of pollution sources, a technical method was established for classification of priority area of soil environmental protection around the river-style water sources. Shunde channel as an important drinking water sources of Foshan City, Guangdong province, was studied as a case, of which the classification evaluation system was set up. In detail, several evaluation factors were selected according to the local conditions of nature, society and economy, including the pollution degree of heavy metals in soil and sediment, soil characteristics, groundwater sensitivity, vegetation coverage, the type and location of pollution sources.

[Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Soils and Sediments in Shunde Waterway, Southern China].

Environmental quality of soils and sediments around water source area can influence the safety of potable water of rivers. In order to study the pollution characteristics, the sources and ecological risks of heavy metals Zn, Cr, Pb, Cu, Ni and Cd in water source area, surface soils around the waterway and sediments in the estuary of main tributaries were collected in Shunde, and ecological risks of heavy metals were assessed by two methods of potential ecological risk assessment. The mean contents of Zn, Cr, Pb, Cu, Ni and Cd in the surface soils were 186.

[Research progress and development trend of quantitative assessment techniques for urban thermal environment.].

Quantitative assessment of urban thermal environment has become a focus for urban climate and environmental science since the concept of urban heat island has been proposed. With the continual development of space information and computer simulation technology, substantial progresses have been made on quantitative assessment techniques and methods of urban thermal environment. The quantitative assessment techniques have been developed to dynamics simulation and forecast of thermal environment at various scales based on statistical analysis of thermal environment on urban-scale using the historical data of weather stations.

[Relationships between settlement morphology transition and residents commuting energy consumption].

Settlement morphology transition is triggered by rapid urbanization and urban expansion, but its relationships with residents commuting energy consumption remains ambiguous. It is of significance to understand the controlling mechanisms of sustainable public management policies on the energy consumption and greenhouse gases emission during the process of urban settlement morphology transition. Taking the Xiamen City of East China as a case, and by using the integrated land use and transportation modeling system TRANUS, a scenario analysis was made to study the effects of urban settlement morphology transition on the urban spatial distribution of population, jobs, and land use, and on the residents commuting energy consumption and greenhouse gasses emission under different scenarios.

Spatial pattern of impervious surfaces and their impacts on land surface temperature in Beijing, China.

Land surface temperature (LST), which is heavily influenced by urban surface structures, is a significant parameter in urban environmental analysis. This study examined the effect impervious surfaces (IS) spatial patterns have on LST in Beijing, China. A classification and regression tree model (CART) was adopted to estimate IS as a continuous variable using Landsat images from two seasons combined with QuickBird.